The present invention relates to a device serving to separate the leading end of a new strip from the trailing end of a depleted strip when renewing the supply of a strip material used by a manufacturing machine.
In particular, the invention relates to a separator device for use in association with changer devices designed to handle relatively rigid strip material, typically paper materials of a certain thickness such as cardboard. To ensure a ready comprehension, reference is made by way of example to devices for changing rolls of cardboard strip as used typically in fashioning the internal reinforcing elements, or frames, fitted to cigarette packets with a hinged lid.
The prior art embraces changer devices such as that disclosed in application no. 3426A/90 for Italian Patent, illustrated here in its entirety to the end of ensuring a comprehensive description; devices of the type comprise an arcuate guide of "U" section along which to direct the strip in use, feed rolls which advance the strip by traction, means by which to distance the trailing end of each depleted strip from the device, and a cutting mechanism by which the strip is severed in the transverse direction. When the moment arrives for the roll to be changed, a second strip from a new roll is directed along the guide, pushed from the rear. Due to the rigid embodiment of the depleted and new strips, and the action of a diverter roller afforded by the concave face of the "U" section guide, the trailing end of the depleted strip and the leading end of the new strip are caused to overlap, disposed with the end of the new strip nearer to the diverter roller than that of the depleted strip. Before the overlapping ends of the new and depleted strips can reach the cutting mechanism together, the trailing end of the depleted strip is taken up by the distancing means and directed away toward a waste drop.
Users of these devices have encountered problems of a practical nature, however, attributable to the mutual adhesion between the two overlapping strips. The effect of the adhesion is such that, at the moment when the trailing end of the depleted strip is taken up by the distancing means, the leading end of the new strip is also diverted toward the waste drop, and manual intervention is required to restore normal operating conditions.
In the case outlined by way of example, certain of the feed rolls serve also to effect longitudinal cuts by which the strips are scored or pierced. These cuts are necessary to the formation of the finished packet, but being made simultaneously in both the new and the depleted strip, their effect is to increase the mutual adhesion in question; as a result, the operation of distancing the trailing end of the depleted strip in isolation is rendered still more difficult, and the changer device can become jammed. The take-up means must be positioned immediately preceding the cutting mechanism in any event, given the need to avoid excessive amounts of waste and reject material.
The object of the present invention is to preclude the risk of mutual adhesion between the two strips resulting in a jam at the changer device.